diff --git a/java/com/google/gerrit/entities/SubmitRequirementResult.java b/java/com/google/gerrit/entities/SubmitRequirementResult.java
index 4f2f2f6..b7fa398 100644
--- a/java/com/google/gerrit/entities/SubmitRequirementResult.java
+++ b/java/com/google/gerrit/entities/SubmitRequirementResult.java
@@ -64,6 +64,13 @@
     }
   }
 
+  /** Returns true if the submit requirement is fulfilled and can allow change submission. */
+  @Memoized
+  public boolean fulfilled() {
+    Status s = status();
+    return s == Status.SATISFIED || s == Status.OVERRIDDEN || s == Status.NOT_APPLICABLE;
+  }
+
   public static Builder builder() {
     return new AutoValue_SubmitRequirementResult.Builder();
   }
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java
index 151ee7b..de637b4 100644
--- a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java
@@ -77,12 +77,17 @@
   @Override
   public Map<SubmitRequirement, SubmitRequirementResult> evaluateAllRequirements(
       ChangeData cd, boolean includeLegacy) {
-    Map<SubmitRequirement, SubmitRequirementResult> result = getRequirements(cd);
+    Map<SubmitRequirement, SubmitRequirementResult> projectConfigRequirements = getRequirements(cd);
+    Map<SubmitRequirement, SubmitRequirementResult> result = projectConfigRequirements;
     if (includeLegacy
         && experimentFeatures.isFeatureEnabled(
             ExperimentFeaturesConstants
                 .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)) {
-      result.putAll(SubmitRequirementsAdapter.getLegacyRequirements(legacyEvaluator, cd));
+      Map<SubmitRequirement, SubmitRequirementResult> legacyReqs =
+          SubmitRequirementsAdapter.getLegacyRequirements(legacyEvaluator, cd);
+      result =
+          SubmitRequirementsUtil.mergeLegacyAndNonLegacyRequirements(
+              projectConfigRequirements, legacyReqs);
     }
     return ImmutableMap.copyOf(result);
   }
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsUtil.java b/java/com/google/gerrit/server/project/SubmitRequirementsUtil.java
new file mode 100644
index 0000000..2e43eac
--- /dev/null
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsUtil.java
@@ -0,0 +1,71 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.project;
+
+import com.google.gerrit.entities.SubmitRequirement;
+import com.google.gerrit.entities.SubmitRequirementResult;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * A utility class for different operations related to {@link
+ * com.google.gerrit.entities.SubmitRequirement}s.
+ */
+public class SubmitRequirementsUtil {
+
+  private SubmitRequirementsUtil() {}
+
+  /**
+   * Merge legacy and non-legacy submit requirement results. If both input maps have submit
+   * requirements with the same name and fulfillment status (according to {@link
+   * SubmitRequirementResult#fulfilled()}), we eliminate the entry from the {@code
+   * legacyRequirements} input map and only include the one from the {@code
+   * projectConfigRequirements} in the result.
+   *
+   * @param projectConfigRequirements map of {@link SubmitRequirement} to {@link
+   *     SubmitRequirementResult} containing results for submit requirements stored in the
+   *     project.config.
+   * @param legacyRequirements map of {@link SubmitRequirement} to {@link SubmitRequirementResult}
+   *     containing the results of converting legacy submit records to submit requirements.
+   * @return a map that is the result of merging both input maps, while eliminating requirements
+   *     with the same name and status.
+   */
+  public static Map<SubmitRequirement, SubmitRequirementResult> mergeLegacyAndNonLegacyRequirements(
+      Map<SubmitRequirement, SubmitRequirementResult> projectConfigRequirements,
+      Map<SubmitRequirement, SubmitRequirementResult> legacyRequirements) {
+    Map<SubmitRequirement, SubmitRequirementResult> result = new HashMap<>();
+    result.putAll(projectConfigRequirements);
+    Map<String, SubmitRequirementResult> requirementsByName =
+        projectConfigRequirements.entrySet().stream()
+            .collect(Collectors.toMap(sr -> sr.getKey().name(), sr -> sr.getValue()));
+    for (Map.Entry<SubmitRequirement, SubmitRequirementResult> legacy :
+        legacyRequirements.entrySet()) {
+      String name = legacy.getKey().name();
+      SubmitRequirementResult projectConfigResult = requirementsByName.get(name);
+      SubmitRequirementResult legacyResult = legacy.getValue();
+      if (projectConfigResult != null && matchByStatus(projectConfigResult, legacyResult)) {
+        continue;
+      }
+      result.put(legacy.getKey(), legacy.getValue());
+    }
+    return result;
+  }
+
+  /** Returns true if both input results are equal in allowing/disallowing change submission. */
+  private static boolean matchByStatus(SubmitRequirementResult r1, SubmitRequirementResult r2) {
+    return r1.fulfilled() == r2.fulfilled();
+  }
+}
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index 4112579..b8c8c07 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -91,6 +91,7 @@
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.project.SubmitRequirementsAdapter;
 import com.google.gerrit.server.project.SubmitRequirementsEvaluator;
+import com.google.gerrit.server.project.SubmitRequirementsUtil;
 import com.google.gerrit.server.project.SubmitRuleEvaluator;
 import com.google.gerrit.server.project.SubmitRuleOptions;
 import com.google.gerrit.server.util.time.TimeUtil;
@@ -969,16 +970,11 @@
         submitRequirements = projectConfigRequirements;
         return submitRequirements;
       }
-      // Get legacy submit requirements, i.e. those created from submit records.
       Map<SubmitRequirement, SubmitRequirementResult> legacyRequirements =
           SubmitRequirementsAdapter.getLegacyRequirements(submitRuleEvaluatorFactory, this);
-      // Combine projectConfigRequirements with legacyRequirements
       submitRequirements =
-          Stream.of(projectConfigRequirements, legacyRequirements)
-              .flatMap(map -> map.entrySet().stream())
-              .collect(
-                  ImmutableMap.toImmutableMap(
-                      Map.Entry::getKey, Map.Entry::getValue, (value1, value2) -> value1));
+          SubmitRequirementsUtil.mergeLegacyAndNonLegacyRequirements(
+              projectConfigRequirements, legacyRequirements);
     }
     return submitRequirements;
   }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index ed9f2f3..52202d7 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -4539,6 +4539,129 @@
       value =
           ExperimentFeaturesConstants
               .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)
+  public void
+      submitRequirements_returnOneEntryForMatchingLegacyAndNonLegacyResultsWithTheSameName_ifLegacySubmitRecordsAreEnabled()
+          throws Exception {
+    // Configure a legacy submit requirement: label with a max with block function
+    configLabel("build-cop-override", LabelFunction.MAX_WITH_BLOCK);
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            allowLabel("build-cop-override")
+                .ref("refs/heads/master")
+                .group(REGISTERED_USERS)
+                .range(-1, 1))
+        .update();
+
+    // Configure a submit requirement with the same name.
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("build-cop-override")
+            .setSubmittabilityExpression(
+                SubmitRequirementExpression.create(
+                    "label:build-cop-override=MAX -label:build-cop-override=MIN"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    // Create a change. Vote to fulfill all requirements.
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+    voteLabel(changeId, "build-cop-override", 1);
+    voteLabel(changeId, "Code-Review", 2);
+
+    // Project has two legacy requirements: Code-Review and bco, and a non-legacy requirement: bco.
+    // Only non-legacy bco is returned.
+    ChangeInfo change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(2);
+    assertSubmitRequirementStatus(
+        change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.SATISFIED,
+        /* isLegacy= */ false,
+        /* submittabilityCondition= */ "label:build-cop-override=MAX -label:build-cop-override=MIN");
+
+    // Merge the change. Submit requirements are still the same.
+    gApi.changes().id(changeId).current().submit();
+    change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(2);
+    assertSubmitRequirementStatus(
+        change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.SATISFIED,
+        /* isLegacy= */ false,
+        /* submittabilityCondition= */ "label:build-cop-override=MAX -label:build-cop-override=MIN");
+  }
+
+  @Test
+  @GerritConfig(
+      name = "experiments.enabled",
+      value =
+          ExperimentFeaturesConstants
+              .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)
+  public void
+      submitRequirements_returnTwoEntriesForMismatchingLegacyAndNonLegacyResultsWithTheSameName_ifLegacySubmitRecordsAreEnabled()
+          throws Exception {
+    // Configure a legacy submit requirement: label with a max with block function
+    configLabel("build-cop-override", LabelFunction.MAX_WITH_BLOCK);
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            allowLabel("build-cop-override")
+                .ref("refs/heads/master")
+                .group(REGISTERED_USERS)
+                .range(-1, 1))
+        .update();
+
+    // Configure a submit requirement with the same name.
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("build-cop-override")
+            .setSubmittabilityExpression(
+                SubmitRequirementExpression.create("label:build-cop-override=MIN"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    // Create a change
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+    voteLabel(changeId, "build-cop-override", 1);
+    voteLabel(changeId, "Code-Review", 2);
+
+    // Project has two legacy requirements: Code-Review and bco, and a non-legacy requirement: bco.
+    // Two instances of bco will be returned since their status is not matching.
+    ChangeInfo change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(3);
+    assertSubmitRequirementStatus(
+        change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.SATISFIED,
+        /* isLegacy= */ true,
+        // MAX_WITH_BLOCK function was translated to a submittability expression.
+        /* submittabilityCondition= */ "label:build-cop-override=MAX -label:build-cop-override=MIN");
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.UNSATISFIED,
+        /* isLegacy= */ false,
+        /* submittabilityCondition= */ "label:build-cop-override=MIN");
+  }
+
+  @Test
+  @GerritConfig(
+      name = "experiments.enabled",
+      value =
+          ExperimentFeaturesConstants
+              .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)
   public void submitRequirements_returnForLegacySubmitRecords_ifEnabled() throws Exception {
     configLabel("build-cop-override", LabelFunction.MAX_WITH_BLOCK);
     projectOperations
@@ -5197,6 +5320,30 @@
       Collection<SubmitRequirementResultInfo> results,
       String requirementName,
       SubmitRequirementResultInfo.Status status,
+      boolean isLegacy,
+      String submittabilityCondition) {
+    for (SubmitRequirementResultInfo result : results) {
+      if (result.name.equals(requirementName)
+          && result.status == status
+          && result.isLegacy == isLegacy
+          && result.submittabilityExpressionResult.expression.equals(submittabilityCondition)) {
+        return;
+      }
+    }
+    throw new AssertionError(
+        String.format(
+            "Could not find submit requirement %s with status %s (results = %s)",
+            requirementName,
+            status,
+            results.stream()
+                .map(r -> String.format("%s=%s", r.name, r.status))
+                .collect(toImmutableList())));
+  }
+
+  private void assertSubmitRequirementStatus(
+      Collection<SubmitRequirementResultInfo> results,
+      String requirementName,
+      SubmitRequirementResultInfo.Status status,
       boolean isLegacy) {
     for (SubmitRequirementResultInfo result : results) {
       if (result.name.equals(requirementName)